Robert hentschel



Aug. 28, 1928. 1,682,336

R. HENTscHEI.

SUCTION DEVICE FOR MULTISTAGE GENTRIFUGAL PUMPS Filed. March 18, 1926Patented Aug. 2s, 192s.

IRQBEBT HENTSCHEL, OF BREMEN, GERMNY.

i PATENT oFFicE.

SVUCTIQN DEVCE FOR MULTISTAGE CENTRIFUGAL-PUMPS.

Application led MarchrlS, 1926, Serial No- 95,591, and in Germany April11, 1925;V

This invention relates to a suction device for multi-stage centrifugalpumps by means of a hydraulically operated jet air pump, and it has, incomparison withthe commonly known suction devices of'this type for itsobject a simplification of construction and operation and saving ofpower by utilizing Afor the production of the pressure in the water forworking of the jet air pump the muliti-stage centrifugal pump to beevacuate z 1 An embodiment of the invention is illustrated, by way ofexample', in the accompanying drawing in which:

Fig. 1 's a vertical longitudinalsection through a two-stage :form ofconstruction.

Fig. 2 is a cross section on line 2 2 of Fig. 1.

Fig. the lower half of the centrifugal pump with another valvearrangement between the two pumpstages.

Fig. 4; is a cross section corresponding with that of Fig. 2 showing amodification of the jet pump.

Fig. 5 shows, on larger scale, a longitudinal section through the upperhalf of the centrifugal pump shownin Fig. 1 comprising an arrangementfor the return of leak 'water into the water circulation of the jet airpump and Fig. 6 shows in section a constructional detail of the jet airpump.

The rst stage with the impeller a is separated from the second stagewith an impeller b' by a spring-controlled ring valve c so that for thesecond impeller b a comparatively large inlet space or flow channel,`

e. g. the annular space d, extending between the two stages is created.The jet air pump e communicates by pipe f with the pressure space g ofthe second stage, by pipe 7e,- with the suction space i oithe firststage and by pipe lo with the annular space Z.'

For operating the-jet air pumpe the inlet space Z oi the .second stageis almost completely filled with water, and after the shutting oii'device or the regulating slide valve m has been closed the shaft n ofthe entriiugal pump carrying the two impelle s a, b is revolved. Acontinuous flow of water through the jet nozzle o of thek air pump e isthus produced the air being sucked o from the suction space e' of theirststage through the pipe L. The sucked oi air iiowsl with the workingwater .in circulation into 3 is a longitudinal section' through theouter annular space p of the impeller b Where it is separated at thehighest point of the water level and escapes into the atmosphere throughthe floating valve g and port 'l'. The circulating ywater flows throughthe upper slot s of the inner annular space Z in the intermediate casingback into the s'econd impeller. The annular space d and the annularspace p may form one single space.

If, afterthe suction, the impeller Va begins to deliver, the waterpressure produced at this occasion opens the ring-valve 0 and closes thefloating valve g. By the opening- ,of lthe regulating Valve m thecentrifugal pump begins now to deliver and the air Vpump e may-be shutoff by the closing of the ]et 'waterand air-pipe so that from thismoment it does not consume any energy.

The shutting oi' of the jet air pump may beei'ected, as-indicated inFig. 5, by means of cocks t, u inthe pipes f and k. In the form ofconstruction shown in Fig. 6 the shutting off is simplified by thearrangement that the jet waterand air-pipes f, l1. may be simultaneouslyshut olil ple way cock w.

-For the rmg valve 'o one or several other by a common multi- V shuttingod devices may be substituted, for

instance after the manner of the' check flap w of Fig. 3.

Under general conditions the use of a mixing nozzle, such as y, Fig.2'of suitable. di

mensions and having a single tapered portion directly connecting withthe jet pump e will be found suliicient for securing an aspi-ratingaction of required suction force t0' eect a vacuumizing of the suctionstage and the filling of the same with water from the source of supplyin a rapid manner and within a reasonable period of time. ln someinstances, however, the operation might be unduly prolonged because 1ofi4 unfavorable head conditions and the presence in the supply line ofa large amount of air or gas tending to unseat the valve c and to reducethe suction force of the jet air pump. For

thepurpose of meeting such conditions I,

provide a compound type of mixing nozzle, such as shown in Fig. 4, inwhich a tapered nozzle portion y of greaterlen'gth than the taperedportion y otFig. 2 is employed together with a second tapered portion ornozzlez. l The mixed air and water flowing successively throughthese'nozzles causes an increased velocity flow of the water, with anincrease of'suction 1n the pump e, and a Tbetween said compression ofthe air flowing with the water into the space Z, whereby an increase ofpressure in the space d is created, prosuction space or into the firstimpeller, the

leal; water can be returned into the circulating-water circulation.cording to Fig. 5, in such a manner that the leali-unter -tlowing oli'bushing is collected in an annular space 2 and sucked oil' again throughthe channel 3 by the jetA airpump.

In more than two-stage centrifugal pumps several stages may be used forsucking olf the air, and inversely.

I claim 1. A multistage centrifugal pump having ay suction stage, acompression stage provided with a valved outlet, a flow passage betweensaid stages, a hydraulically operated jet air pump operative under waterpressure produced in said pressure stage, conducting connections betweensaid jet air pump and said suction and compression stages, means foropening or closing said connections for opening or closing communicationbetween said jet air pump and said suction and pressure. stages, and avalve normally closing said flow passage and adapted to open under apredetermined pressure in the suction stage.

2. A multistage centrifugal pump having a suction stage, a compressionstage provided with a valved outlet, a flow passage stages, a water andair chamber between the stages and in communication with the flowpassage, said chamber having an air vent outlet, a valve governed by thewater level in said chamber and controlling said vent outlet, ahydraulically operated jet air pump operative under water pressureproduced in said pressure stage, connections between said jet air pumpand said suction and compression stages, means for opening or closingcommunication between said jet'air pump and said suction and pressurestages, and a valve normally closing said flow passage and adapted toopen under a predetermined pressure in the suction stage.

3. A multistage centrifugal pump having a suction stage and a pressurestage, a, hy-

draulically operated jet air pump operative under water pressureproduced in said pressure stage, air and water flow channels between thejet air pump and the suction and pressure stages, a flow passage betweenthe pressure stage and suction stage, an automatic valve controllingsaid passage, and means controlling said channels for open` This isetfected, ac-

through the shaftpressure stage,

ing and closing communication between the jet air pump and the suctionand pressure stages. v

4. A multistage centrifugal pump having a suction stage and a pressurestage, a hydraulically operated jet air pump operative by water pressureproduced in the pressure stage and including a mixing nozzle, a flowpassage between the suction and pressure stages, a normally closed valvegoverning said passage and adapted to open under a predeterminedpressure in the suction stage, valve cont-rolled conductors forconnecting said jet air pump with the suctionand pressure stages, and asecond mixing nozzle connected to said' mixing nozzle of said jet airpump for converting into pressure the flow energy of the water and airmixture so as to hold the valve governing the flow passage closedagainst pressure in the suction stage when the jet air pump is inaction.

5. A multistage centrifugal pump having a suction stage, a pressurestage provided with a valve controlled outlet, a water and air chamberdisposed between said stages, a liow passage between said stages andcommunicating at its highest level with said chamber, a normally closedvalve controlling communication between the suction stage and saidpassage and adapted to open under a predetermined pressure in thesuction stage, an automatic vent for the discharge of air from the Waterand air chamber, a hydraulically operated jet air pump operative underwater pressure produced in the pressure stage, air and water flowchannels respectively connecting said jet air pump with the suction andpressure stages, valves for opening and closing said channels, and amixing pipe connecting the water and air chamber with the jet air pump.

6. A multistage centrifugal pump having a suction stage, a pressurestage provided with a valve controlled outlet, an air and water chamberbetween said stages provided with an air vent outlet, a liow passagebetween saidstages Communicating at its highest level with the water andair chamber, a normally closed valve controlling communication betweensaid passage and the suction stage and adapted to open under apredetermined pressure in the suction stage, a hydraulically tive underwater pressure produced in the conductors connecting the jet air pumpwith the suction and pressure stage and theair and water chamber,respectively, valves for opening and closing the conducoperated jet airpump operators between the jet air pump and the sucz water chamberbetween said stages provided with an airy vent outlet, a flow passagebetween said stages communicating at lits highest level with the waterand air chamber, a normally closed valve controlling communicationbetween said passage and the suction stage and adapted to open under apredetermined pressure in the suction stage, a-hydraulically operatedjet air pump o erative y 10 under water pressure produced in t epressure stage, conductors connecting thel suction and pressure stageswith said jet air pump, valves for opening and closing said conductors,and a conductor connecting the air and water chamber with vthe jet airpump', said conductor being provided .with a plurality of mixingnozzles.

In testimony whereor` I aflx my signature.

ROBERT HENTSCHEL.

